Determination of organochlorine pesticides in UHT and pasteurized milk

This study was carried out for the purpose of developing two different methods and analysis of organochlorinated pesticides in different commercial brands of UHT or pasteurized milk. The difference was created in the sample preparation part. While in the first method extraction was performed from milk sample, in the second method from milk fat. The aim of creating different methods was to obtain high recovery.The method was developed to determine eighteen organochlorinated pesticides (aldrin, 4,4 ?-DDD, 4,4 ?-DDE, 4,4'-DDT, dieldrin, ?-endosulfane, ß-endosulfane, endosulfan-sulphate, endrin, endrin aldehyde, endrin ketone, ?-HCH, ß-HCH, ?-HCH, ?-HCH, heptachlor, heptachlorepoxide, metoxychlor) in milk samples. In the sample preparation part liquid/liquid extraction was used to separate the compounds from milk and milk fat. The samples were analyzed by GC-MS/MS. In order to demonstrate the quality of the method, method validation and uncertainty calculation was performed. Internal standardization technique was used the quantify the results. Pentachloronitrobenzene was used as an internal standard. The average recovery of this compound was 87%. The limit of detection (LOD) of the methods was obtained in between 0,36 - 1,11 µg kg-1 range. These values were below the maximum residue levels of Turkish Food Codex. Sixty UHT and twenty seven pasteurized milk samples were analyzed but no residues of pesticides were detected. The reason of this result was assumed as the prohibition of pesticide use since many years.